Bog building, also called upflow filter, eco filter, wetland filter

[addy1]

I have mine with a T at the entrance, due to the length of my pipes we cut the slots further apart near the input, closer near the end of the pipes. (26 feet long)

This is the 5th summer coming up. No clogging of the pipes. I do not draw from the bottom of the pond. But for some reason my pond does not develop a lot of mulm / muck on the bottom, it stays pretty clean. Clean enough the spilled pea gravel on the bottom is very easily seen.

If you put the piping around the edge like you are showing. I would point the openings more towards the interior of the container. i think if they point up the edge you might end up with tracking, ie the water will got up the side of the container rather than through the gravel. Or keep you pipes at least 6-8 inches from the sides. IMHO lol You need to make the water work to get out, it does find the easiest way out, a smooth container side is the easiest way out.

 

[falconut]

OK, here's another pass. I shifted the tee to the inlet side, using a loop with a single cleanout and moved the loop away from the sides. The slots will be on the bottom, just showing them for representation. I'm thinking of using 1-1/2" hose, then increase the inside pipe to 2", with two 2" outlet pipes.

 

[addy1]

the only problem i see is the clean out. if one side is plugged the water would just go down the unplugged side

 

[falconut]

the only problem i see is the clean out. if one side is plugged the water would just go down the unplugged side

So, should I just not connect the loop and have two cleanouts at the ends?

 

[Catfishnut]

I have been following this thread since I discovered it.

Addy, thanks for taking the time to put it together. I have found it to be very informative.

Falco, looking over your design, I am wondering if it would be better to set your inlet and outlet connections along the long axis of the stock tank, as opposed to the short axis. If your stock tank is near the same dimensions as mine, the long axis is 6 to 8 feet, but the short width axis is only 24 to 30 inches.

If you set this up so that the water flows across the short axis, I think you will be diminishing your filtering capabilities of the bog. If you change this so that the water flows throught the long axis from inlet to outlet ports, I think you will acheive much better filtration and the plants will absorb more of the nutirents from the fishes waste.

Looking at your diagrams, is seems that the two rounded ends of the tank are simply going to be dead spaces. Meaning that there wil be no activity or water flow through them. This appears to me to be a waste of a great deal of surface area that you could otherwise take advantage of if you directed the flow along the long axis of the tank.

I guess what I am hinting at here is that if you change the flow axis, the water wil have more residence time within the bog. More plants will be able to service the pond water and there will be more mechanical and biological filtration occuring before the water returns to the pond.

Addy, you are the noted expert here on bogs, so I ask you if I am on the proper track with this subject and my evaluation.
I'd like to be right, but I am not sure since I have never attempted a bog before. It is just my gut feeling that it should operate better in the way I have described. What is your opinion?

Gordy

 

[addy1]

lol Gordy, I am only the expert cause I built one and it works great. Did study the subject a lot before building this one in Maryland. I had smaller bog type filters in arizona, this one works so much better than they did.

I am not sure it will make any difference where he has in and out. The piping is what directs the water to flow in and through the gravel. My output is about 1/3 of the way down one edge of the bog, near the input. But with the way we cut the pipes a ton of water flows to the end of the bog, then works its way back to the outflow, which is a water fall.

He won't have a lot of dead space, needs to keep the piping close but not right on the edge of the tank. Our pipes are around a foot from the edge, two feet apart. You can see water bubbling up even near the edge away from the piping. Ours is 4 feet to 4.5 feet wide.

 

[falconut]

Catfishnut - I was going to have the inlet on the long side, but read that you need to have the bulkheads on a flat side, which in only on the side I have them. The container is a smaller one, around 4'x2'x12"height.

Here's my latest thought:


This way I get some flow directly in the middle, maybe I'll use some 45's on the right side to expand it a little. I'll have to see how it look once I get the container and the pipe.

 

[addy1]

"Technically" you could get by with just one pipe with a two foot wide container. But more is better, you just don't want so much flow and fast flow it does not get filtered by the gravel, i.e. shooting through.

I used 2 inch pvc piping, just two for a 4 foot wide area. Not sure I would do three in that size of container you have esp if two inch pvc

 

[Catfishnut]

Catfishnut - I was going to have the inlet on the long side, but read that you need to have the bulkheads on a flat side, which in only on the side I have them. The container is a smaller one, around 4'x2'x12"height.

Here's my latest thought:


This way I get some flow directly in the middle, maybe I'll use some 45's on the right side to expand it a little. I'll have to see how it look once I get the container and the pipe.

Falconut,

I think that I like your initial design with the pipe looped in a hexagon with the 45 degree fittings. You could insert two tees at the ends of the tank's long axis and in the center to accomodate a center tube as well.

In the above diagram, you have two dead ends where debris could accumulate (unless you are going to place a cleanout riser at each of these ends). Your initial design creates a balanced loop as well, so the pressure and flow rate is equalized better throughout the entire pipe.

Also, if you get the outer PVC pipes too close to the outer walls of the tank, the water flow may tend to follow the tank wall up to the surface (like Addy was elluding to earlier). That would create a reduction in the volume of water flowing through the gravel and thus defeating your purpose. With only a 2' wide tank, you would want to keep the pipe more towards the center axis of the tank to avoid this.

I would be tempted to try laying the PVC pipe at the bottom of the tank in a rectangular loop. Then placing some paving bricks at the bottom of the tank to support a grid above the pipes that will serve as a floor for larger rock and then place smaller rock on top of those. This keeps the very bottom few inches of the tank open for easy flushing when necessary.

Place the bulkhead fittings along the long sides of the tank at the very bottom where the wall is "flat" and not curved. Use these as drain and flushing ports. Might just place three of them along one side.

Have the INLET piping just come directly into the tank via a pipe down through the gravel and rock media from the top (not through a bulkhead fitting from the side) and have the purge or cleanout pipe on the opposite end of the long end of the tank.

The water entering your bog tank will have to percolate up through the layers of rock and gravel to the plant roots and then out through piping near the upper layers.

I don't know if my ideas are correct, but I wanted to toss them out here to spur the discussion forward. I like to analyze the water flow and the drainage capabilities in my mind and imagine what could, should and will happen. I am not an engineer regarding such subjects, but I do think about them with great enthusiasm.

I am just hoping that I can bring some ideas to your mind and help you with your project.

Gordy

 

[addy1]

One of my smaller bogs in arizona had the raised bottom, it did work great for flushing the bottom of the bog filter. I used a pvc frame, put light grid on top of it and some screening, then pea gravel. That one was a half of a whiskey barrel. It did need cleaning mainly because it was too small for the pond size and the only filter.
My bog in maryland is so big, no way I could do that, pea gravel too heavy, bog too big.

Mine here, we back flush via the input piping, I have "back flushed" a few times, mainly just because I had to drain it to work on the piping. Nothing but clean water came out. So now unless it shows channeling, or some other issue I will just ignore it.

The only work I do on the bog/pond is yanking overgrowing plants. I can ignore it all summer if need be.

 

[Catfishnut]

Addy,

It sounds like your current bog is set up, sized and planted perfectly. It is actually keeping itself clean!

Gordy

 

[addy1]

Addy,

It sounds like your current bog is set up, sized and planted perfectly. It is actually keeping itself clean!

Gordy

Thanks gordy
Pure luck, some thought, well a lot of thought, but my main reasoning was just to be able to plant a lot of plants and on the side keep the pond clean. I loved how they worked for my other ponds, but they were all too small to do a real good job.

 

[falconut]

OK. With yet another small amount of snow, I think I'm re-thinking my last few layouts. I was going to drill a hole near the bottom side and have a bulkhead with a tee and two valves. This assembly was going to remain during the winter. But, now I'm thinking that with all the snow and ice, it might not be a good idea.

So, I'm leaning towards no holes other than the exits. Have it come in over the side, loop the bottom with a cleanout on the opposite end. Looking at the pipe sizes, I think 1-1/2" will fit my container better, 2" is just too large for 45's. I should be able to shut the pump valve, then open the drain valve and it should siphon the container out (backflush). I should also be able to insert a garden hose to fix a blockage. In the winter, I'll just unscrew the union and remove the assembly, so just two open pipes will be left in the winter. This way the container won't have any low areas that can crack and leak. Here's the layout:


What do you think? Again, the slots are on the bottom of the pipe, probably even aim the slots towards the center for the pipe under the exit pipes. I did buy the container this weekend.

 

[Catfishnut]

Falconut,

That looks pretty darned awesome to me! I like the entire flow and layout. Looks to be quite simple to construct this way, too. No big dilemnas in fabrication to contend with. Easy, simplistic but well thought out design. It appears to be a made to order project and I think it is going to work very well.

Gordy

 

[Catfishnut]

Allow me to add... Your drawing here is immaculate. What did you use to create this image? Very well done.

Gordy